The Dead Zone - Season 2 Episode 11 Playing God

A wild old high school friend, Jason, comes to see Johnny seeking a vision of the future as he will be dying of a heart condition. Johnny sees him receiving a successful heart transplant and gives him the good news, but later gets a vision of Jason's sister Kate being killed in a driving accident and becoming the donor. Johnny later gets a vision of the other driver's license plate while Jason takes a turn for the worse, then sees a vision of him and Kate arguing which leads to her going out and getting in the accident. Johnny soon realizes even if he saves Kate and gets Jason a heart through Purdy's connections, someone else who would have received the heart will die. Johnny tracks down the drunk driver, Patrick Hanchin, and confronts him, but sees that even if Johnny stops him from killing Kate, he'll hit a school bus.